Various vehicle interior lights for visually assisting a driver or passenger, such as, for example, a room lamp, a courtesy lamp, a reading light and a backlight of an instrument panel, are installed inside a vehicle. These vehicle interior lights are so controlled as to be turned on and off in accordance with a switch operation by the user or opening/closing of a vehicle door, for example. Turning on and off of these vehicle interior lights are often controlled by, for example, a body electronic control unit (ECU).
Japanese Patent Application Laid-Open Publication No. 2016-182839 proposes a vehicle interior light control system that aims to prevent decrease in convenience and to reduce unnecessary lighting of a vehicle interior light. In the vehicle interior light control system, an in-vehicle machine that controls turning off of a vehicle interior light which is on performs control to turn off the vehicle interior light if it identifies that a mobile device capable of locking a vehicle door is positioned within a predetermined range outside the vehicle and detects that the vehicle door is locked.